1. Field of the Invention
The present invention relates to an axial fan motor.
2. Description of the Related Art
An axial fan motor for cooling heat generating electronic parts is generally mounted on household electric appliances and various OA/IT equipment. Recently, demand for a large air flow capacity of the axial fan has increased because of the increase in the heat generated by, and the reduction in product costs, of household electric appliance and various OA/IT equipment. When the air flow capacity of an axial fan motor is increased, however, there is a tendency that noise due to an electromagnetic exciting force and rotation of vanes in the axial fan is increased. Further, a demand for noise reduction has increased for the pursuit of a more comfortable environment, and improvements corresponding thereto have been developed.
In JP-A-10-159792, vibration reduction is intended by providing vibration isolating rubber between a motor shaft and a fan boss.
In JP-A-2003-269381, vibration reduction is intended by providing vibration isolating rubber between an inner ring member fitted onto a motor shaft and an outer ring member fitted into a fan boss.
In JP-A-2003-286997, vibration reduction is intended by providing vibration isolating rubber between a fan shaft and a fan body.
In JP-A-07-213005, vibration reduction of a fan motor is intended by the use of an attenuation material.
In all of the above-described patent documents, a vibration attenuation material such as a vibration isolating rubber, etc., is provided in order to achieve vibration reduction, but cannot be considered to be a fundamental measure for reducing vibration since a vibration source and the vibration isolating rubber are in contact with each other.
Meanwhile, it is desirable that a stator core and a sleeve, which supports the stator core, be separated from each other as far as possible for the purpose of vibration reduction and noise reduction, and it is preferred that a contact area between the stator core and the sleeve be made small. Recently, recycling of resources is advocated, and products which may be disassembled and recycled are desired for axial fan motors.
A stator core and a sleeve, which supports the stator core, in conventional fan motors and blowers are joined together by measures such as bonding, caulking, welding, etc., but when a stator core is fixed to the sleeve by such measures, disassembly cannot be performed unless the sleeve is broken, so that recycling of the resource cannot be achieved.